The present invention relates to a magnifier and, more particularly, to a retractable magnifier with an electric lamp.
It is well known that magnifiers are useful tools for observe small objects or for relieving the eyestrain during the observation. A magnifier that has a lens retractable into a protective housing is disclosed, such as in U.S. Pat. No. 5,754,349, which is a retractable magnifier provided with a protective housing and an additional lamp. Although such a magnifier can be operated with a single hand, it still has some shortcomings as follows:
The lamp can not function anymore once a lens of the magnifier is fully retracted into the housing.
Even if the lens is extended out, there is only a fraction of light that can be out of the housing through a window. This fraction of light then travels in a direction substantially transverse to the housing and so the object to be observed can not be illuminated properly.
Because the lens is carried in a frame which is moved directly by the action of two springs, the frame and the lens are moved at a rapid speed immediately after they are actuated to extend out of the housing, thus resulting in a significant impact upon associated stop elements and a shortened life of the magnifier.
In this magnifier, there is no proper guide for the movement of the frame. Because it is impossible either for the two springs to exert absolutely equal action to the frame or for the two push-buttons to be depressed at the exactly same time, the frame may be jammed in the housing if one of its opposite side is moved to precede the other.
It is an object of the present invention to provide a retractable magnifier which may overcome the shortcomings of the prior art. Another object of the present invention is to provide a retractable magnifier in which a lens assembly may be extended out and retracted in smoothly.
Yet another object of the present invention is to provide a retractable magnifier in which a lens assembly may be extended out slowly and gently.
Still another object of the present invention is to provide a retractable magnifier in which a lamp functions effectively.
To achieve the aforementioned objects, the present invention provides a retractable magnifier comprising a housing and a lens assembly having a lens carried in a frame. The lens assembly is movable in the housing between a retracted position and an extended position. The housing is provided with push-buttons capable of releasing the lens assembly from the retracted position. A longitudinal rack is formed in the housing. A pinion meshes the rack and has a spindle rotatably connected to the frame. The pinion further includes a helical torsion spring mounted around the spindle and placed in damping oil for urging the pinion in such a direction that the frame may be moved, in a gentle manner, to the extended position. A rocker provided with an electric prefocus lamp is pivotally connected to the housing, and adapted to be pivoted outward at a predetermined angle with the housing when the lens assembly is in the extended position. A switch is formed on the housing for turning on/off the lamp.
As an aspect of the present invention, the rack and the pinion are made of plastic.
In a highly preferred embodiment, the housing has a pair of spaced tabs formed therein, and the rocker has a shaft rotatably connected to the spaced tabs.
The rocker and the shaft made be made of plastic into an integral configuration.
The rocker and the shaft may also be made separately of plastic and then attached to each other, and the rocker may be is spring-loaded so as to tend to be pivoted inward and orientated at a substantially zero angle with the housing.
As another aspect of the present invention, the frame of the lens assembly has an inner end formed with a protrusion, and the protrusion is configured to pivot the rocker outward through the predetermined angle when the lens assembly is moved to the extended position.
Additionally, the electric prefocus lamp may be a small, electric prefocus bulb or, alternatively, may be a light emitting diode.
As still another aspect of the present invention, the retractable magnifier further comprises at least one battery received in the housing.
As yet another aspect of the present invention, the retractable magnifier further comprises an internal plastic casing filled with the damping oil, and the helical torsion spring is placed in the damping oil.
Other objects, advantages and novel features of the this invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.